In how many ways can 7 different books be arranged on a shelf? In many ways three particular books are always together?

In how many ways can 5 different books be arranged on a shelf if (i) there are no restrictions (ii) 2 books are always together (iii) 2 books are never together

In how many ways can 12 books be arranged on a shelf if 4 particular books must always be together.

In how many ways 7 books can be arranged from 10 books?

In how many ways 10 different books can be arranged in an almirah such that a particular book (1) is always taken (2) is never taken